Stop Your Itchin'

No matter what body part needs scratching, we have a soothing solution

That's right—you, the one who just scratched his arm. And you, excavating your scalp. There's treatment for that, you know!

"Pruritus" means itching. And being a guy means scratching. Everyone itches, many different times in many different places, sometimes all over all at once. For such a common condition, however, doctors aren't exactly sure what's going on. Or why scratching feels so good. It's a tantalizing mystery, as unreachable as a mosquito bite in the middle of your back.

"I was attracted to the Zen nature of the symptom," says Jeffrey D. Bernhard, M.D., a dermatology professor at the University of Massachusetts and editor of Itch: Mechanisms and Management of Pruritus. "It's paradoxical: Dermatology is perhaps the most visual of all medical specialties, yet [in the case of pruritus] you can't see the most important symptom."

For ages, doctors and scientists thought itches traveled the same neural pathway as pain. That theory has changed in the past decade. "We now know that itching has its own special pathway," says Adnan Nasir, M.D., Ph.D., an assistant clinical professor of dermatology at the University of North Carolina at Chapel Hill.

The sensation of itching is transmitted by tiny C-fiber nerves (the body's smallest) that extend nearly to the skin's surface. These C-fibers can be activated directly by an irritant that gets into your skin (through cracks), or indirectly by immune-system cells that patrol the skin and release histamine when they detect something foreign (such as mosquito spit). The histamine binds to the nerve endings, which send a message to the brain that the skin needs attention.

Pain uses a different set of C-fibers. "Pain causes a withdrawal response," Dr. Bernhard says. "Itching causes a response that makes you want to go toward the site of the itching."

Oh, does it ever. Why does scratching work, at least temporarily? "The brain can process only one signal of sensation at a time from a particular location in the skin," explains Dr. Nasir, "and by providing another type of irritation, we can suppress the itch." He also points out that scratching generates heat, "and if you heat up the nerves that cause itching, you can suppress it."

Which leaves the issue of why scratching feels so dang good. If you follow the "human urge to scratch, you're going along a well-trodden neurological pathway that is hardwired into the brain. It's very satisfying," Dr. Nasir says. Medicines or tricks (see below) that suppress itching are sometimes "not as gratifying." That shudder of pleasure may be from a "release of endorphins that give you a natural high," he says.

Too much scratching, however, can trigger an "itch-scratch cycle," in which the scratching aggravates the body into releasing more histamine, which causes swelling, which stimulates nerve endings, which causes more itching. . . .

You need to break the cycle. We'll show you how, particularly with some classic male itches. First, some all-purpose tricks.

• Ice it. Cold tends to make the C-fibers sluggish.

• Fool it. Scratch the corresponding spot on the opposite limb. Nerves on one side of the body run up the other side of the spine, and somehow "it tricks the brain," says Dr. Nasir.

• Ignore it. Play a game on your Sony PSP to distract your brain. A recent Australian study published in BMC Pediatrics found that allowing kids to play a virtual-reality video game while they were being treated for burns resulted in reduced pain and itching.

It makes more sense to understand and attack the source of the itch than to battle it once it has arrived. Here's your guide.